Propellant charge for small arms ammunition



US. Cl. 102-38 Unite States Patent M 3,442,213 PROPELLANT CHARGE FOR SMALL ARMS AMMUNITION Teruhiko Suzuki, Nobeoka-shi, Junichi Nomura and Daijiro Kameyama, Dita-shi, and Minoru Miyoshi, Sokashi, Japan, assignors to Asahi Kasei Kogyo Kabushiki Kaisha, Kita-ku, Osaka, Japan, a corporation of Japan Filed Apr. 18, 1967, Ser. No. 631,580 Claims priority, application Japan, May 23, 1966, 41/ 32,435 lint. (ll. F42b 5/02 2 Claims ABSTRACT OF THE DISCLOSURE A large amount of water-soluble substances having uniform particle size are mixed with a propellant composition arbitrarily selected from the group consisting of single-base, double-base and triple-base powder. The mixture thus obtained is shaped into a desired shape according to a conventional method, and thereafter the shaped propellant is submerged in water to elute out water-soluble substances, thereby to obtain a porous structure.

The thus obtained propellant has a high burning rate and is capable of being used as a propellant charge of single grain. This propellant charge can be used as a caseless cartridge by fixing a bullet to one end of said propellant charge and a priming device to the other.

Conventional propellant powder for small arms ammunition is composed of many grains of propellant powder in the shape of a ball, flake or tube. Accordingly, a cartridge case is required to maintain the propellant powder therein. Still more, troublesome operations are required, for example, to weight correctly the propellant powder on loading and to eject a waste case from a gun after firing.

Conventional propellant charge must be composed of many grains; because the combustion surface thereof must be large to a certain extent to ignite it easily and smoothly and to obtain desired ballistic properties. In order to simplify the shooting operation, there has been attempted molding multiple grains of propellant powder into a desired shape by using a binder. The resulting propellant, however, has poor ignitability due to a large fluctuation of its combustion area and interior physical properties, e.g., compression strength, tensile strength etc. Accordingly, it has unstable ballistic properties.

The present invention relates to a propellant charge for small arms ammunition. An object of the present invention is to provide a solid propellant charge consisting of a single grain having excellent ignitability and ballistic properties, free from the above-mentioned drawbacks. Another object of this invention is to provide a solid propellant charge having uniform combustion area and superior physical properties. It has been found that these objects and other advantages can be attained by the propellant charge consisting of single grain shaped without a binder and having a porous structure.

The propellant charge of this invention is shaped into a grain having a cross section of a circular, square, hexagonal, octagonal, rosette, T, cross, asterisk or the like and is substantially solid and without perforations and/ or grooves, or has at least one perforation.

The invention will be described in further detail hereinafter with reference to the attached drawing, wherein:

FIG. 1 is a flow sheet of the method of the invention, and

FIG. 2 is a diagrammatic sectional view of a caseless cartridge according to the invention.

3,442,213 Patented May 6, 1969 The most desirable method of producing the propellant charge is as follows; mixing 40-150 parts by weight of water-soluble substance having a limited particle size selected from the range between 30a and 250 with parts by weight of propellant composition arbitrarily selected from the group consisting of single-base, doublebase and triple-base propellants, kneading the resulting composition with addition of 10-150 parts of a solvent, then pressing the thus kneaded mixture into a cord of desired cross section and then cutting the resultant cord into a desired length. The thus obtained green grain is immersed in water for several days, to elute out the watersoluble substance homogeneously dispersed in the grain, and then dried. The finer the particle size of water-soluble substance and the larger the amount thereof mixed, the higher the burning rate of the product. However, range of particle size and amount are limited from the standpoint of ignition property and physical properties of the propellant charge. Particles of a size larger than 250 cause lack of uniformity in size and distribution of the pores within the propellant charge, whereby the ignitability and the ballistic properties of the propellant charge are made unstable. On the contrary, when the particle size is smaller than 30p. the ignitability of the propellant charge is poor, even if the mixing amount thereof is increased. When a water-souble substance having a range of particle size fom 30,11. to 250,11. is used, the mixing amount thereof is preferably in the range of from 40 to parts based on the 100 parts by weight of the propellant composition. If an amount is less than 40 parts, it tends to give the product poor ignitability. On the other hand, if the amount is above 150 parts, it tends to give the product poor physical properties whereby an abnormally high chamber pressure is liable to be caused. Accordingly, in order to obtain a propellant charge having desired ballistic properties, a water-soluble substance having limited particle size in the range of from 30 to 250,00 must be added in an amount ranging from 40 to 150 parts based on 100 parts by weight of the propellant composition. The present propellant charge is desirable to have a porosity of approximately 25-60% of the whole grain. The water-soluble substances employed, include inorganic salts, e.g., sodium chloride, potassium chloride, sodium nitrate, potassium nitrate, sodium sulfate, potassium sulfate, and organic materials, e.g., sugars, glucose. As a solvent, there may be used any which are commonly used in the production of propellant powder by those skilled in the art. Further, there may additionally be used as a plasticizer, diethylphthalate, dibutylphthalate, dinitrotoluene or the like. The shape of the cross section of the present propellant charge can be circular, square, hexagonal, octagonal, rosette, T, cross, asterisk or the like according to the purpose of use. For some usages, the present propellant charge may be shaped to have some perforations and/or grooves.

The propellant charge of this invention shows almost the same ignitability, physical properties and ballistic properties as the conventional propellant powder. Further it burns completely without foulings. The propellant charge of this invention is put into practice in two ways, e.g., using it with or without a cartridge case. In the case of utilizing the present charge with a cartridge case it is used in the usual way without a weighing operation. In the other case, as shown in FIG. 2, the propellant charge 1 is combined with a priming device 2 and a bullet 3 without a cartridge case. -In the latter case, it is readily understood that an expensive metallic case which represents 40-50% of the total cost of a cartridge can be eliminated, which simultaneously results in a reduction of the weight per cartidge and thereby facilitates easy transportation of the ammunition. Further, such operations as weighing the propellant powder and ejecting a waste cartridge case after iring are not required any longer. Accordingly, it may ,afely be said from the general point of view that the :mployment of the present propellant charge provides an :poch-making effect in an attempt to reduce the cost of tmmunition and simplify the shooting operation.

This invention is illustrated by some examples but is rot limited thereby.

4 32 g. of shots (No. 7 /2 chilled). Five rounds were fired for each sample.

Further, at the same time, conventionally known flake propellant powder for hunting (Mach, trademark, registered by Asahi Chemical Industry Co., Ltd.) was tested under the same conditions for the sake of comparison. Both results obtained are shown in Table 2.

TABLE 2 conventionally known propellant (Maeh, trademark registered by Sample of propellant charge Asahi Chemical Example 1 To 100 parts of the following single-base composition used as a propellant powder for a hunting shotgun, potassium nitrate having a particle size of 74-149 was added respectively in an amount of 50, 70, 90 and 110 parts.

Single-base composition Percent Nitrocellulose (nitrogen content:13.15%) 98.81 Diphenylamine 1.19

To the resulting mixture, 110 parts of a solvent of etherzalcohol (65:35) was added. After being homogeneously kneaded, the resultant mixture was pressed using a pressing machine equipped with a die having the following dimensions and shaped to obtain a 7-perforated tubular cord having a rosette cross-section and cut into grains of 12.4 mm. in length.

Mm. Diameter (outer) 17.2 Diameter (inner) 15.1 Diameter of each perforation 2.3

The shaped propellant thus obtained, which still contains the solvent therein, was immersed in hot water at about 50 C. for 5 days while agitating and replenishing the hot water to elute out the potassium nitrate and solvent, and was dried at 55 C. for 48 hours. The amount of potassium nitrate to be finally retained within the propellant was determined to be less than 1%. Bulk density, porosity and compress-ion strength were measured on four samples. The results of the measurements were compared with those obtained with a conventional single base propellant of flake formed grains. The results obtained are shown in Table 1.

(A) To 100 parts of the following single-base composition, 100 parts of sodium chloride having a particle size of 4474,LL was added and mixed.

Single-base composition Percent Nitrocellulose (nitrogen content:l3.20%) 99.10 Dinitrodiphenylamine 0.90

To the mixture thus obtained, 110 parts of a solvent of etheraalcohol (:35) was added. After being homogeneously kneaded, the resultant mixture was pressed using a pressing machine equipped with a die having the following dimensions, and shaped to obtain a 7-perforated tubular cord having a circular cross section, and cut into grains of 7.52 mm. in length.

Diameter 6.46 Diameter of perforation 0.53

By following the same procedure as in Example 1, sodium chloride and the solvent were eluted out from the grains and the grains were dried at 55 C. for 48 hours.

(B) To 100 parts of the following double-base composition, 100 parts of potassium nitrate having a particle size of 44-74 was added and mixed.

Double-base composition Percent Nitrocellulose (nitrogen content=13.15%) 77.- Nitrogenglycerine 21.60 Ethyl centralite 0.70

To the mixture thus obtained, 20 parts of a solvent of acetonezalcohol (45:55) was added. After being homo- As apparent from the above results, with the amount of KNO porosity, bulk density and compression strength varied. However, when the amount of KNO is between 50-110 parts, there is no substantial difference in the physical strength as compared with that of conventional propellant powder. Next, 1.90 g. of each of four samples Diameter 6.12

was loaded in a paper case for a shotgun of No. 12 with Diameter of perforation 2.24

Potassium nitrate and the solvent were eluted out by use of water at 20 C. and the grains were dried at 50 C. for 48 hours.

(C) To 100 parts of the following triple-base composition, 100 parts of potassium nitrate having a particle size Min. Diameter (outer) 11.40 Diameter of perforation 1.52

According to the same procedure as in Example 1,

. 5 potassium sulfate and the solvent were eluted out from of 44-74 was added and named the grains, and the grains were dried at 55 C. for 48 hours. Tnple'base composmon To one end of the thus obtained propellant charge, a .45 Percent caliber lead bullet (14.90 g. as weighed) was fixed with Nitrocellulose (nitrogen cOntent=12 60% 2800 1 an epoxy adhesive, and to the other end, the same priming Nitroglycerine 2250 sheet as n Example 2 was adhered to prepare the case- Nitroguanidine 4730 less cartridge. Nine caseless cartridges thus prepared were Ethyl Centralite L80 fired by use of a gun having been modified in chamber and percussion section. At the same time, conventional .45 To the mixture thus Obtained, 15 parts of a Solvent of 19 caliber cartridges (flake single-base propellant being used) acetone:alcohol (35:65) was added. After being hornowere also .fired for the Sake of Comparison B h results geneously kneaded, the resultant mixture was pressed are Shown m Table using a pressing machine equipped with a die having the TABLE 4 following dimensions, and shaped to obtain 7-perforated 20 Sample ofcartridgc tubular cord having a circular cross section, and cut into grains of 9.05 mm. in length. 3X3 Mm. Item cartridge carti idge Dtameter eateratagate??E"iie s%::---;::: 5 3 Diameter of perforation 0.43 Combustion residue None None Average velocity (In/sec.) 263. 4 252.3 Potassium nitrate and the solvent were eluted out by ifggggg i gf i figggfifigf gjgfij" 35% 1, 395 use of water at 20 C. and the grains were dried at 50 C. Standard deviation 74 32 for 24 hours.

Each of the resultant single-base, double-base and triple- We claim: base charges were employed to obtain caseless blank 1. Apropellant charge for small arms ammunition concartridges by adhering priming sheets to each charge. Said sisting of a single grain having a porous structure, which is priming sheets are obtained by coating on a cotton tape produced by mixing 40-150 parts by weight of a waterwith a muddy mixture of priming composition of soluble substance having a limited particle size in a range DDNP:KClO (1:1) and 3% crude rubber dissolved in a 35 between 30 1. and 250,11. with 100 parts by weight of protoluol solution, drying the coated cotton tape and then pellant composition, kneading the resulting composition cutting the dried cotton tape into a circular base of 10 with addition of solvent, forming the kneaded mixture into mm. in diameter. a desired shape to obtain a green grain, and immersing Five rounds of each of the blank cartridges thus prothe thus obtained green grain in water for several days duced was fired. At the same time, a commercial blank to elute out the water-soluble substance homogeneously cartridge (containing fiake propellant charge) for a rivet dispersed therein, and then drying the obtained grain. gun were fired under the same conditions as above for 2. In combination with the propellant charge of claim 1, the sake of comparison. Both results obtained are shown a priming device at one end thereof and a bullet at the in Table 3. other end thereof to form a caseless cartridge.

TAB LE 3 Shape of propellant Amount of Combuspropellant tion Depth of penetration of a pin (111111.)

Sample of blank cartridge employed charge (g.) residues Highest Lowest Deviation Average The present blank cartridges." Single-base 7-perforated tubular grain." 0. 15 None.. 7. 9 6. 5 1. 4 7. 3 Double-base... Single perforated tubular 0.15 do 8.4 6.8 1. 6 7.5 Triple-base.-- 'iififiated tubular grain O. 15 do 8.1 6.4 1 7 7.2 Commercial blank cartridge Single-hasten Flake 0.15 do 8.1 6.6 1 6 7.4

As apparent from the above results, the present propel- H References Cited lant charges show almost same ignitability and strength UNITED STATES PATENTS as those of commercial charges.

547,222 10/1895 Maxim 102100 X Example 3 552,919 1/1896 Maxim 102-101 To 100 parts of the following single-base composition, 677,528 7/1901 Maxim 102100 100 parts of potassium sulfate having a particle size of 766,455 8/1904 Maxim 102100 44-74, was added and mixed. 1,077,320 11/1913 Walsh 10299 1 b 3,014,427 12/1961 Scurlock 102100 mg ase compo 3,054,353 9/1962 Rumpp et al 102 100 Percent Nitrocellulose (nitrogen content=13.15%) 99.1 FOREIGN PATENTS Dlphenylamme 488,819 7/1938 Great Britain.

To the mixture thus obtained, 110 parts of a solvent of etherzalcohol (65:35) was added. After being homogeneously kneaded, the resultant mixture was pressed using a pressing machine equipped with a die having the following dimensions, and shaped to obtain a 5-perforated tubular cord having an X-form cross section, and cut into grains of 7.54 mm.

U.S. Cl. X.R. 

